Wells, William D., author
Prentice-Hall, 2000
Buku Teks
Gomez, Julita R.
National Book Store, 1986
Buku Teks
Sutherland, Max, author
PPM, 2004
Buku Teks
Forceville, Charles
Routledge, 1996
Buku Teks
Reichert, Gene
Alexander Hamilton Institute, 1972
Buku Teks